▎ 摘　　要

NOVELTY - A photodetector consists of silicon nanocrystalline layer and graphene layer, which are sequentially arranged on n-type silicon substrate, front electrode and back electrode arranged below n-type silicon substrate. The resistivity of n-type silicon substrate is 1-10 Omega /cm. The silicon nanocrystalline layer is obtained by spin coating hydroxysilsesquioxane and annealing at high temperature. The thickness of silicon nanocrystalline layer is 0.5-0.8 mu m. The front electrode comprises titanium/gold electrode and is in contact with graphene layer and back electrode comprises titanium/gold/titanium electrode and is in contact with silicon substrate. USE - Photodetector. ADVANTAGE - The photodetector effectively responds to UV, visible and near-infrared optical wide spectrum ranges, and achieves signal doubling through a photo-switching effect between silicon nanocrystalline layer and graphene layer. The preparation process is simple and compatible with the complementary metal-oxide-semiconductor process. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for preparation of photodetector, which involves cleaning n-type silicon substrate, preparing silicon nanocrystalline layer, fabricating back electrode layer and graphene layer, depositing a gold layer having thickness of 30-50 nm on graphene layer and obtaining copper foil etching solution.